Frame-shaped composite material molding mold and frame-shaped composite material molding method

Abstract

The application provides a frame-shaped composite material forming die and a frame-shaped composite material forming method, and belongs to the technical field of composite material die forming equipment design. The die comprises a female die, a male die and a top cover plate. A forming ring cavity is formed on the top surface of the female die. The male die comprises a middle pressing ring, an inner side pressing ring on the inner side of the middle pressing ring and an outer side pressing ring on the outer side of the middle pressing ring. The outer ring wall surface of the inner side pressing ring is in contact with the inner ring wall surface of the middle pressing ring. The inner ring wall surface of the outer side pressing ring is in contact with the outer ring wall surface of the middle pressing ring. The middle pressing ring, the inner side pressing ring and the outer side pressing ring can jointly form a block to the cavity opening of the forming ring cavity, so as to die form the composite material in the forming ring cavity into a frame-shaped blank. The middle pressing ring can be positioned and connected with a machining equipment. The top cover plate is arranged on the side of the male die away from the female die. The application effectively reduces the accumulation of positioning errors, is beneficial to improving the consistency of product size and the product qualification rate, and improves the production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of composite material molding equipment design technology, specifically relating to a frame-type composite material molding die and a frame-type composite material molding method. Background Technology

[0002] Planar frame composite parts are widely used in aerospace, rail transportation, high-end equipment and other fields. These parts usually have complex assembly steps and multiple assembly through holes, and have extremely high requirements for dimensional accuracy, surface quality and molding consistency.

[0003] In the existing technology, there are two main solutions for processing such parts:

[0004] The first type is one-time compression molding, which directly forms the assembly steps and through holes of the product through the mold. However, the complex steps of the frame parts make it extremely difficult to lay the prepreg, and problems such as bridging, insufficient glue, and excessive porosity are likely to occur. The step size accuracy is difficult to control, and the molding defect rate is extremely high, which cannot meet the high-precision assembly requirements.

[0005] The second method involves molding the blank and then demolding it for secondary machining. This method first uses a molding die to mold the composite material into a blank. After the blank is removed from the molding die, it is re-clamped and positioned on the machine tool to complete the step milling and through hole drilling. However, this method requires repeated clamping due to the need to make room for the machining area. The molding datum and the machining datum are not consistent, the positioning error accumulates greatly, and the product size consistency is poor. At the same time, the clamping process is prone to crushing and deformation of the composite material parts, resulting in deviations in the product machining size, low product qualification rate, and low production efficiency. Summary of the Invention

[0006] Therefore, the present invention provides a frame-type composite material molding die and a frame-type composite material molding method, which can overcome the shortcomings of the existing technology that uses the method of first preparing composite material blanks and then performing secondary machining. This method requires repeated clamping, the molding datum and the machining datum are not consistent, the positioning error accumulates greatly, and the clamping process is prone to crushing and deformation of composite material parts, resulting in deviations in product processing dimensions, low product qualification rate, and low production efficiency.

[0007] To address the aforementioned problems, this invention provides a frame-type composite material molding die, comprising a female mold, a male mold, and a top cover plate. A molding ring cavity is formed on the top surface of the female mold. The male mold includes a central pressure ring, an inner pressure ring located inside the central pressure ring, and an outer pressure ring located outside the central pressure ring. The outer ring wall of the inner pressure ring contacts and engages with the inner ring wall of the central pressure ring, and the inner ring wall of the outer pressure ring contacts and engages with the outer ring wall of the central pressure ring. The central pressure ring, inner pressure ring, and outer pressure ring together seal the opening of the molding ring cavity to mold the composite material within the molding ring cavity into a frame-type blank. The central pressure ring can be positioned and connected to the worktable of a machining equipment. The top cover plate is positioned on the side of the male mold opposite to the female mold.

[0008] In some embodiments, the intermediate pressure ring is made of a ferromagnetic metal material so that the intermediate pressure ring can be magnetically positioned and connected to the worktable; and / or, at least two positioning pin holes are formed on the end face of the intermediate pressure ring facing away from the female mold, and each positioning pin hole can be inserted into a positioning pin on the worktable.

[0009] In some embodiments, the frame-shaped blank has multiple through holes, and the intermediate pressure ring forms a set hole in the area corresponding to each of the through holes. A locking screw is inserted into each of the set holes and through holes, and the screw head of the locking screw is located at the end of its screw shank closer to the female mold. A nut is screwed onto the threaded section of the screw shank away from the female mold.

[0010] In some embodiments, the bottom wall of the forming ring cavity has a groove for accommodating each screw head in the area corresponding to the position of each through hole, and the groove and the screw head are anti-rotationally engaged; and / or, the end of the set through hole away from the female mold is a countersunk platform, the nut is accommodated in the countersunk platform, and the end of the screw rod away from the female mold is located in the countersunk platform; and / or, the screw rod has a first rod segment that mates with the set through hole and a second rod segment that mates with the through hole, the wall of the set through hole is a conical surface that mates with the first rod segment, and the minor diameter surface of the first rod segment is located at the end away from the female mold.

[0011] In some embodiments, a sealing washer is fitted on the screw rod, and in use, the sealing washer is embedded in the slot of each of the grooves and its top surface is flush with the bottom wall plane of the molded ring cavity; and / or, an axial limiting ring platform is formed at the connection between the first rod segment and the second rod segment.

[0012] In some embodiments, the inner pressure ring is composed of multiple inner pressure ring sub-bodies spliced ​​together, and multiple first guide posts are formed on the top surface of the female mold, which are spaced apart around the outer edge of the forming ring cavity. Each inner pressure ring sub-bodies is respectively fitted with at least two adjacent first guide posts for upper and lower limiting. Or, the outer pressure ring is composed of multiple outer pressure ring sub-bodies spliced ​​together, and multiple second guide posts are formed on the top surface of the female mold, which are spaced apart around the inner edge of the forming ring cavity. Each outer pressure ring sub-bodies is respectively fitted with at least two adjacent second guide posts for upper and lower limiting. Alternatively, the intermediate pressure ring has a pressure ring body and an extension plate extending toward the inner pressure ring and / or the outer pressure ring. The extension plate stops on the end face of the inner pressure ring and / or the outer pressure ring away from the female mold, and the extension plate and the end face of the pressure ring body away from the female mold are on the same plane.

[0013] In some embodiments, a limiting annular groove capable of accommodating the male mold is formed on the end face of the top cover plate facing the male mold.

[0014] In some embodiments, the female mold is further provided with a plurality of limiting grooves that are spaced apart around the periphery of the molding ring cavity and penetrate the outer wall of the female mold. Each limiting groove contains a push-out demolding component. Each push-out demolding component has a lifting plate that is below the bottom surface of the frame-shaped blank and flush with the bottom wall of the molding ring cavity, and a force-applying block that extends to the outer wall of the female mold. Each push-out demolding component can apply force to the bottom surface of the frame-shaped blank through the force-applying block to demold the frame-shaped blank from the molding ring cavity.

[0015] The present invention also provides a method for molding a frame-type composite material using the frame-type composite material molding die described above, comprising the following steps:

[0016] The screw heads of each screw rod are positioned in each groove from top to bottom, and the prepreg with pre-made through holes is laid layer by layer in the forming ring cavity. Each prepreg is fitted onto each screw rod through its through hole, and each prepreg is laid layer by layer to reach a preset thickness to form a block.

[0017] The middle pressure ring, inner pressure ring and outer pressure ring are placed on the female mold to realize the closing of the male mold and the female mold, and a top cover plate is placed on the top surface of the male mold;

[0018] After the mold is closed, it is placed in a hot press to complete the molding and curing process to form a frame-shaped blank.

[0019] Remove the top cover plate, screw a nut onto the threaded section of the locking screw to ensure that the frame blank and the intermediate pressure ring are reliably connected as one unit, then demold the frame blank, each locking screw and the male mold as a whole from the forming ring cavity, and after demolding, detach the inner pressure ring and the outer pressure ring from the frame blank;

[0020] The frame-shaped blank is positioned and connected to the worktable of the machining equipment via the side end face opposite to the frame-shaped blank through the intermediate pressure ring;

[0021] Select one of the locking screws as the reference screw, obtain the positional deviation between the original machining coordinate system of the worktable and the reference coordinate system corresponding to the center of the screw head of the reference screw, and when the positional deviation is higher than a preset threshold, establish the actual machining coordinate system with the screw head of the reference screw as the reference, and perform machining on the frame blank to form a frame composite material finished product based on the actual machining coordinate system.

[0022] In some implementations...

[0023] After the material block is pasted and formed, and before the male mold and female mold are closed, the process further includes: removing the formed material block from the molding ring cavity, and using unidirectional carbon fiber bundles to pass through two adjacent through holes to form a cross hole in the thickness direction of the material block for clamping, and then placing the clamped material block back into the molding ring cavity; or,

[0024] When the intermediate pressure ring has a positioning pin hole and the intermediate pressure ring is made of a ferromagnetic metal material, with the magnetic switch on the worktable of the machining equipment in the off state, the intermediate pressure ring is inserted into the positioning pin on the worktable via the positioning pin hole to form an insertion fit, and then the magnetic switch is controlled to switch from the off state to the closed state; or...

[0025] When the positional deviation is not higher than the preset threshold, the frame blank is machined to form a frame composite material finished product based on the original machining coordinate system of the worktable.

[0026] The frame-type composite material molding die and frame-type composite material molding method provided by the present invention have the following beneficial effects:

[0027] The male mold is formed by three parts: an inner pressure ring, an inner pressure ring, and an outer pressure ring, which are fitted together. After the frame-shaped blank is molded, the inner and outer pressure rings, located inside and outside the inner pressure ring, can be removed from the blank. The inner pressure ring is then used to position and connect with the worktable of the machining equipment, and the outer or inner circumference of the frame-shaped blank can be machined (e.g., trimming, milling steps, and holes). The machining reference and the molding reference are both the inner pressure ring, realizing the sharing of the molding die between the molding and machining processes. Further machining of the molded blank can be achieved without repeated clamping, effectively reducing the accumulation of positioning errors and eliminating the damage and deformation caused to composite material parts by repeated clamping in the existing technology. This is beneficial to improving the consistency of product dimensions and the product qualification rate, and increasing production efficiency. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. The drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0029] Figure 1 This is a three-dimensional structural diagram (part disassembly) of a frame-type composite material molding die in one embodiment of the present invention.

[0030] Figure 2 yes Figure 1 A top view of the male mold in its usage state;

[0031] Figure 3 yes Figure 2 A cross-sectional view of the male mold AA in one embodiment;

[0032] Figure 4 yes Figure 2 A cross-sectional view of the male mold AA in another embodiment;

[0033] Figure 5 yes Figure 1 A three-dimensional structural diagram of the top cover plate and the male mold from another perspective;

[0034] Figure 6 This is a schematic diagram showing the state of the frame-shaped blank after it has been demolded from the molding ring cavity and the inner and outer pressure rings have been separated from the blank.

[0035] Figure 7 yes Figure 6 A schematic diagram of the locking screw in the middle;

[0036] Figure 8 yes Figure 1 Top view of the central female mold in use;

[0037] Figure 9 yes Figure 8 Cross-sectional view of BB in the middle.

[0038] The attached figures are labeled as follows:

[0039] 1. Female mold; 11. Forming ring cavity; 111. Groove; 12. First guide post; 13. Second guide post; 2. Male mold; 21. Intermediate pressure ring; 211. Locating pin hole; 212. Tightening through hole; 213. Extension plate; 22. Inner pressure ring; 221. Inner pressure ring body; 23. Outer pressure ring; 231. Outer pressure ring body; 24. Pressure ring pin hole; 3. Locking screw; 31. Screw head; 32. Screw rod; 320. Axial limiting ring platform; 321. First rod segment; 322. Second rod segment; 33. Sealing washer; 34. Nut; 4. Top cover plate; 41. Limiting ring groove; 5. Push-out demolding component; 51. Lifting plate; 52. Force application block; 100. Frame-type blank; 101. Through hole. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0042] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90° or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0043] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0044] See also Figures 1 to 9 As shown, according to an embodiment of the present invention, a frame-type composite material molding die is provided, including a female mold 1, a male mold 2, and a top cover plate 4. A molding ring cavity 11 is formed on the top surface of the female mold 1. The male mold 2 includes a central pressure ring 21, an inner pressure ring 22 located inside the central pressure ring 21, and an outer pressure ring 23 located outside the central pressure ring 21. The outer ring wall surface of the inner pressure ring 22 is in contact with the inner ring wall surface of the central pressure ring 21, and the inner ring wall surface of the outer pressure ring 23 is in contact with the central pressure ring 21. The outer ring wall of the intermediate pressure ring 21 is in contact with the inner ring 22 and the outer ring 23. Together, they seal the opening of the molding ring cavity 11 (reducing glue leakage during the molding process of the prepreg) to mold the composite material within the molding ring cavity 11 into a frame-shaped blank 100. The intermediate pressure ring 21 can be positioned and connected to the worktable of a machining equipment. The top cover plate 4 is placed on the side of the male mold 2 facing away from the female mold 1. The aforementioned contact fit refers to, for example... Figure 3As shown, the outer ring wall of the inner pressure ring 22 and the inner ring wall of the middle pressure ring 21 are fitted together and tightly fitted to form a sealing effect on the contact surface. At the same time, the two can be easily disassembled. Similarly, the inner ring wall of the outer pressure ring 23 and the outer ring wall of the middle pressure ring 21 are fitted together and tightly fitted to form a sealing effect on the contact surface. At the same time, the two can be easily disassembled. It should be noted that, in order not to affect the machining of the frame blank 100, the size of the inner ring wall of the intermediate pressure ring 21 should be larger than the size of the inner ring wall of the finished frame composite material, and the size of the outer ring wall of the intermediate pressure ring 21 should be smaller than the size of the outer ring wall of the finished frame composite material. That is, when the intermediate pressure ring 21 and the finished frame composite material are assembled together, the inner ring wall of the finished frame composite material protrudes from the inner side of the inner ring wall of the intermediate pressure ring 21, and the outer ring wall of the finished frame composite material protrudes from the outer side of the outer ring wall of the intermediate pressure ring 21. In a specific embodiment, the size of the outer peripheral wall of the intermediate pressure ring 21 (that is, the aforementioned inner ring wall and outer ring wall) is 0.5-2mm smaller on one side than the outer peripheral wall of the finished product.

[0045] In this technical solution, the male mold 2 is formed by three parts: an inner pressure ring 21, an inner pressure ring 22, and an outer pressure ring 23, which are fitted together. After the frame blank 100 is molded, the inner pressure ring 22 and the outer pressure ring 23, which are located inside and outside the inner pressure ring 21, can be removed from the blank. The inner pressure ring 21 is used to position and connect with the worktable of the machining equipment to perform machining on the outer or inner periphery of the frame blank 100 (e.g., trimming, milling steps and holes). The machining reference and the molding reference are both the inner pressure ring 21, realizing the sharing of the molding mold between the molding process and the machining process. Further machining of the molded blank can be achieved without repeated clamping, which effectively reduces the accumulation of positioning errors and can eliminate the damage and deformation caused to composite material parts by repeated clamping in the prior art. This is conducive to improving the consistency of product dimensions and the product qualification rate, and improving production efficiency.

[0046] It is understandable that, since the aforementioned intermediate pressure ring 21 serves as part of the male mold 2 and also as an assembly positioning component in the machining process (similar to a traditional liner), its dimensional and positional accuracy requirements are high. Specifically, the two end faces of the intermediate pressure ring 21 should be precision machined with a flatness of ≤0.02mm and a parallelism of ≤0.02mm between it and the bottom wall of the forming ring cavity 11.

[0047] In some embodiments, the intermediate pressure ring 21 is made of a ferromagnetic metal material, such as Cr12MoV steel precision-machined in a specific embodiment, so that the intermediate pressure ring 21 can be magnetically positioned and connected to the worktable. It is understood that the worktable of the aforementioned processing equipment should have a corresponding magnetic attraction structure, which controls the magnetic attraction force of the magnetic attraction structure by controlling the on and off of the corresponding magnetic attraction switch, thereby realizing the magnetic connection between the intermediate pressure ring 21 and the worktable. The magnetic connection is used to realize the positioning connection of the frame blank 100 on the worktable. The operation is simple and convenient, greatly improving the efficiency of positioning the blank, and there is no risk of clamping deformation of the frame blank 100.

[0048] In some embodiments, at least two positioning pin holes 211 (e.g., blind holes) are formed on the side end face of the intermediate pressure ring 21 facing away from the female mold 1. Each positioning pin hole 211 can correspond one-to-one with the positioning pins on the worktable (not shown in the figure) to form an insertion fit. In a specific embodiment, there are two positioning pin holes 211, and the two positioning pin holes 211 are arranged opposite to each other at intervals.

[0049] In this technical solution, the circumferential positioning of the frame blank 100 is achieved by forming a one-to-one insertion fit between the positioning pin on the worktable and the positioning pin hole 211 on the intermediate pressure ring 21.

[0050] In one specific embodiment, the diameter of the aforementioned positioning pin hole 211 is 6mm, and the aforementioned positioning pin is a cylindrical pin.

[0051] In order to ensure a reliable connection between the aforementioned frame blank 100 and the intermediate pressure ring 21 after demolding, and thus ensure the smooth progress of subsequent machining of the frame blank 100, it is also necessary to use relevant components to connect the frame blank 100 and the intermediate pressure ring 21 into one unit. For example, a clamping component can be used to limit the two before the intermediate pressure ring 21 is positioned and connected to the worktable. In some embodiments, the frame blank 100 has multiple through holes 101. The intermediate pressure ring 21 and the area corresponding to the position of each through hole 101 form a locking through hole 212. Locking screws 3 are inserted into the locking through holes 212 and through holes 101 corresponding to each position. The screw head 31 of the locking screw 3 is located at the end of its screw shank 32 close to the female mold 1. A nut 34 is screwed onto the threaded section of the screw shank 32 away from the female mold 1. In one specific embodiment, the aforementioned frame-shaped blank 100 has four through holes 101, each through hole 101 being located in one of the four corner areas of the frame, and the aforementioned locking screws 3 also have four corresponding through holes 101.

[0052] In this technical solution, the frame-shaped blank 100 and the intermediate pressure ring 21 can be reliably connected as one unit by the locking screw 3 and the nut 34 screwed to it. This effectively prevents the blank 100 from detaching from the intermediate pressure ring 21 during the machining process on the aforementioned worktable, ensuring that the position of the frame-shaped blank 100 is reliable and stable. The structure is simple. At the same time, the locking screw 3 can also be used as a reference for the machining coordinate system, improving the machining accuracy.

[0053] In some embodiments, the bottom wall of the molded annular cavity 11 has a groove 111 formed in the area corresponding to the position of each through hole 101 for accommodating each screw head 31. The groove 111 and the screw head 31 are anti-rotationally fitted. This anti-rotationally fit means that when the screw head 31 is placed in the corresponding groove 111, the rotational freedom between them is locked, i.e., rotation around the central axis of the screw head 31 is not possible. For example, the screw head 31 and the groove 111 are hexagonal and matched. It is understood that the axial height of the screw head 31 should not exceed the groove depth of each groove 111.

[0054] In this technical solution, by setting a groove 111 on the bottom wall of the forming ring cavity 11 to accommodate each screw head 31, the bottom end face of the blank can be subjected to uniform force, which is beneficial to improving the molding quality of the blank.

[0055] In some embodiments, a sealing washer 33 is fitted onto the screw rod 32. In use, the sealing washer 33 is embedded in the grooves 111 with its top surface flush with the bottom wall of the molded ring cavity 11. The sealing washer 33 forms a continuous plane between the groove openings 111 and the bottom wall of the molded ring cavity 11, preventing prepreg from leaking into the grooves 111 and resulting in a smoother bottom surface of the blank, free of steps and indentations. In one specific embodiment, the sealing washer 33 is made of polytetrafluoroethylene (PTFE), which facilitates demolding from the product after processing.

[0056] In some embodiments, the end of the locking through hole 212 facing away from the female mold 1 is a recessed platform (not indicated in the figure). The nut 34 is housed in the recessed platform, and the end of the screw rod 32 away from the female mold 1 is located in the recessed platform. That is, during the molding process, the free end (tail end) of the screw rod 32 is hidden inside the recessed platform. In this way, the bottom end surface of the top cover plate 4 does not need to be provided with a corresponding housing structure for the free end of the screw rod 32, which reduces the manufacturing difficulty of the top cover plate 4 and makes the force transmission of the top cover plate 4 more uniform.

[0057] In some embodiments, the screw rod 32 has a first rod segment 321 that mates with the set through hole 212 and a second rod segment 322 that mates with the through hole 101. The wall of the set through hole 212 is a conical surface that mates with the first rod segment 321, that is, the outer wall surface of the first rod segment 321 is also a conical surface, and the small diameter surface of the first rod segment 321 is located at the end away from the female mold 1. In a specific embodiment, the taper of the conical surface of the first rod segment 321 is 1:50 to 1:100, the mating length of the first rod segment 321 and the intermediate pressure ring 21 is 10 to 15 mm, and the contact rate of the mating surfaces of the two is ≥80%, which can ensure sufficient connection rigidity and self-locking force, ensuring that it will not loosen during processing and will not cause difficulties in disassembly and assembly. In another embodiment, in order to facilitate the demolding of the second rod segment 322 from the blank, the second rod segment 322 is provided with a draft angle of 0.5° to 1°, preferably 0.8°.

[0058] It should be noted that the first rod segment 321 and the fixed through hole 212 adopt a tapered surface fit. When the mold is closed, the intermediate pressure ring 21 is automatically pressed into the tapered fit segment under the pressure of the press, forming an interference fit of 0.01~0.02mm, realizing a zero-clearance rigid connection and automatic centering, with a coaxiality ≤0.01mm. This fit eliminates the clearance problem of cylindrical clearance fit, effectively resists the lateral cutting force during machining, and avoids workpiece displacement.

[0059] An axial limiting ring platform 320 is formed at the connection between the first segment 321 and the second segment 322, as detailed below. Figure 7 As shown, there is a diameter difference at the connection between the first rod segment 321 and the second rod segment 322, which forms the aforementioned axial limiting ring platform 320. The axial limiting ring platform 320 can mechanically limit the downward pressure position of the intermediate pressure ring 21, preventing excessive clamping of the blank in the thickness direction when the aforementioned nut 34 is tightened after the blank is formed, thus preventing damage to the blank.

[0060] See Figure 2 As shown, in one embodiment, the inner pressure ring 22 is composed of multiple inner pressure ring sub-bodies 221 spliced ​​together. Multiple first guide posts 12 are formed on the top surface of the female mold 1, spaced apart around the outer edge of the forming ring cavity 11. Each inner pressure ring sub-bodies 221 is respectively fitted with at least two adjacent first guide posts 12 for upper and lower positioning. And / or, the outer pressure ring 23 is composed of multiple outer pressure ring sub-bodies 231 spliced ​​together. Multiple second guide posts 13 are formed on the top surface of the female mold 1, spaced apart around the inner edge of the forming ring cavity 11. Each outer pressure ring sub-bodies 231 is respectively fitted with at least two adjacent second guide posts 13 for upper and lower positioning. Figure 2As shown, the inner pressure ring 22 and the outer pressure ring 23 each include four inner pressure ring sub-bodies 221 and four outer pressure ring sub-bodies 231, with each sub-pressure ring sub-bodies corresponding to one side of the frame. See details. Figure 3 As shown, the top surfaces of the inner pressure ring body 221 and the outer pressure ring body 231 are flush with the top surface of the middle pressure ring 21 (with the orientation in the use state as a reference). At this time, each of the aforementioned inner pressure rings 22 and outer pressure rings 23 is provided with a pressure ring pin hole 24 that corresponds to each of the first guide post 12 and the second guide post 13, thereby limiting the horizontal position of each pressure ring body and enabling the pressure ring body to be easily detached from it from bottom to top after the blank is formed, which is beneficial for subsequent machining operations on the blank.

[0061] The fit clearance between each guide post (i.e. the aforementioned first guide post 12 and second guide post 13) and the corresponding pressure ring pin hole 24 is 0.02~0.05mm, which ensures positioning accuracy and facilitates disassembly and assembly.

[0062] In some embodiments, the top cover plate 4 has a limiting annular groove 41 formed on the side end face facing the male mold 2, which can accommodate the male mold 2, such as... Figure 5 As shown, the inner and outer contours of the groove wall of the limiting ring groove 41 match the inner and outer ring wall contours of the aforementioned male mold 2. Thus, during the process of the top cover plate 4 being pressed down, each pressure ring body is fastened together by the limiting ring groove 41 of the top cover plate 4, forming a comprehensive constraint of the top cover plate 4 on each pressure ring body in the radial (horizontal), circumferential, and height directions. This ensures that each pressure ring body forms an organic whole during the molding process, without displacement or movement, and avoids the formation of misalignment gaps that cause prepreg to run out of glue.

[0063] See Figure 4As shown, in another embodiment, the intermediate pressure ring 21 has a pressure ring body and an extension plate 213 extending toward the inner pressure ring 22 and / or the outer pressure ring 23. The extension plate 213 stops on the end face of the inner pressure ring 22 and / or the outer pressure ring 23 opposite to the female mold 1, and the extension plate 213 and the end face of the pressure ring body opposite to the female mold 1 are on the same plane. This increases the magnetic contact area between the intermediate pressure ring 21 and the worktable, thereby improving the connection reliability between the worktable and the intermediate pressure ring 21. It should be noted that the top cover... A limiting ring groove 41 is formed on the side end face of the plate 4 facing the male mold 2, which can accommodate the male mold 2. The limiting ring groove 41 reliably limits the aforementioned inner pressure ring body 221 and outer pressure ring body 231 in the horizontal and vertical directions. It can be understood that, at this time, due to the obstruction of the aforementioned extension plate 213, the aforementioned first guide post 12, second guide post and pressure ring pin hole 24 are no longer provided between each pressure ring body and the female mold 1, so as to ensure that after the top cover plate 4 is removed from the top surface of the male mold 2, each pressure ring body can be horizontally removed from the blank in the horizontal direction, either outward or inward.

[0064] In some embodiments, the female mold 1 is further provided with a plurality of limiting grooves (not indicated in the figure) that are spaced apart around the periphery of the molding ring cavity 11 and penetrate the outer wall of the female mold 1. Each of the limiting grooves contains a push-out demolding component 5. See details below. Figure 9 As shown, each of the ejector demolding components 5 has a lifting plate 51 located below the bottom surface of the frame-shaped blank 100 and flush with the bottom wall (top surface) of the molding ring cavity 11, and a force-applying block 52 extending to the outer wall of the female mold 1. Each ejector demolding component 5 can apply force (e.g., manually pry) to the bottom surface of the frame-shaped blank 100 via the force-applying block 52 to demold the frame-shaped blank 100 from the molding ring cavity 11. See details. Figure 9 As shown, the top surface of the lifting plate 51 of the ejector 5 objectively serves as part of the bottom wall of the molding ring cavity 11, and the inner vertical wall of the force application block 52 objectively serves as part of the outer vertical wall of the molding ring cavity 11. The gap between it and the limiting groove should be as small as possible while facilitating demolding and lifting, to prevent the prepreg from running out of the prepreg. In one embodiment, the fitting gap between the ejector 5 and the limiting groove is ≤0.03mm to avoid flash caused by running out of the prepreg during curing. In other embodiments, the mating surface between the ejector 5 and the main body of the female mold 1 is provided with a demolding slope of 3°~5° to achieve smooth demolding of the product edge and avoid scratches.

[0065] According to an embodiment of the present invention, a method for molding a frame-type composite material using the above-described frame-type composite material molding die is also provided, comprising the following steps:

[0066] The screw heads 31 of each screw rod 32 are positioned from top to bottom in each groove 111, and the prepreg material (such as T700 carbon fiber prepreg) with pre-made through holes 101 is laid layer by layer in the forming ring cavity 11. During the laying process, the prepreg material should be flat, without bridging or wrinkles. Each prepreg material is fitted onto each screw rod 32 through its through holes 101. Each prepreg material is laid layer by layer to reach the preset thickness. The prepreg material of the preset thickness forms a whole, that is, a block. It can be understood that the upper and lower surfaces of each layer of prepreg material have adhesive material so that the upper and lower layers of prepreg material can be bonded together.

[0067] The middle pressure ring 21, inner pressure ring 22, and outer pressure ring 23, i.e., the male mold 2 as a whole, are placed on the female mold 1 to achieve mold closing between the male mold 2 and the female mold 1. A top cover plate 4 is placed on the top surface of the male mold 2. When the inner pressure ring 22 and outer pressure ring 23 respectively include multiple inner pressure ring sub-bodies 221 and outer pressure ring sub-bodies 231, and the top cover plate 4 has a limiting ring groove 41 on the end face of the side near the male mold 2, it should be ensured that the top surface of each pressure ring sub-bodies is placed in the limiting ring groove 41. Thus, the limiting ring groove 41 is used to effectively constrain the position of each pressure ring sub-bodies in the height direction, horizontal left and right direction, front and back direction, and circumferential direction, reducing the gaps between each pressure ring sub-bodies and between the middle pressure ring 21 and the inner and outer pressure rings. This reduces glue leakage and improves the top surface molding quality of the blank.

[0068] After the mold is closed, it is placed in a hot press device (with pressure and heating functions, such as a hot press or press) to complete the molding and curing according to the prepreg curing process to prepare a frame blank 100. The aforementioned prepreg curing process can be, for example, curing at 120°C and 0.6MPa pressure for 2 hours. It is understood that when the locking screw 3 has the aforementioned axial limiting ring 320, when the pressure head under the hot press device applies pressure to the top cover and squeezes each layer of prepreg in the molding ring cavity 11 along its stacking height direction, the axial limiting ring 320 can mechanically limit the downward pressure of the intermediate pressure ring 21 to prevent excessive pressure on the prepreg from damaging the prepreg and thus reducing the product molding quality.

[0069] Remove the top cover plate 4, and screw the nut 34 onto the threaded section of the locking screw 3 to ensure that the frame blank 100 and the intermediate pressure ring 21 are reliably connected as one. It is understood that during the screwing of the nut 34, the intermediate pressure ring 21 will not cause extrusion damage to the blank under the axial limiting action of the aforementioned axial limiting ring platform. At the same time, since the screw head 31 of the locking screw 3 is limited to the groove 111 on the bottom wall of the forming ring cavity 11 to prevent rotation, the nut 34 is reliably screwed. Then, the frame blank 100, each locking screw 3 and the male mold 2 are demolded from the forming ring cavity 11. After demolding, the inner pressure ring 22 and the outer pressure ring 23 are removed from the frame blank 100. At this time, the inner edge area and the outer edge area of ​​the frame blank 100 are exposed to facilitate further machining operations on the blank. The intermediate pressure ring 21 forms a reliable whole under the action of the locking screw 3 and the nut 34.

[0070] The frame-shaped blank 100 is positioned and connected to the worktable of the machining equipment via the side end face of the intermediate pressure ring 21 that is away from the frame-shaped blank 100.

[0071] Then, one of the locking screws 3 is selected as the reference screw, that is, one of the four locking screws 3 is selected as the reference screw. The positional deviation between the original machining coordinate system of the worktable (the original machining reference of the worktable) and the reference coordinate system corresponding to the center of the screw head 31 of the reference screw is obtained. When the positional deviation is higher than the preset threshold, it indicates that the deviation between the original machining coordinate system of the worktable and the actual size of the frame blank 100 is large. The actual machining coordinate system should be established with the screw head 31 of the reference screw as the reference, and the frame blank 100 should be machined based on the actual machining coordinate system to form a frame composite material finished product. When the positional deviation is not higher than the preset threshold, it indicates that the deviation between the original machining coordinate system of the worktable and the actual size of the frame blank 100 is small, which meets the requirements of machining accuracy. Therefore, in this case, the frame blank 100 can be machined based on the original machining coordinate system of the worktable to form a frame composite material finished product, which can significantly improve the machining efficiency of the frame blank 100. In one specific embodiment, the aforementioned preset threshold can be, for example, 0.02 mm. Of course, depending on the actual requirements for machining accuracy, the aforementioned preset threshold can be appropriately increased or decreased. It should be noted that, since the first segment 321 of the locking screw 3 and the set hole 212 of the intermediate pressure ring 21 have a tapered surface fit, it can ensure that the position between the blank and the intermediate pressure ring 21 is reliable and stable during machining, further improving the machining accuracy of the product.

[0072] In this technical solution, the intermediate pressure ring 21 serves as part of the molding die and can also be used as a positioning and connecting component (as a liner) during the machining process. Meanwhile, the locking screw 3 serves as a connecting component between the blank and the intermediate pressure ring 21 and as a reference for the machining coordinate system, which can significantly improve the machining accuracy of the product.

[0073] It should be noted that, since damage to the outer periphery of the blank is inevitable during the demolding process of the blank from the female mold 1, and the dimensional accuracy of the outer periphery of the blank is relatively low, the accuracy of the machining coordinate system can be ensured by using the locking screw 3 as the reference of the machining coordinate system and ensuring the machining accuracy of the locking screw 3.

[0074] When the ejector mold 5 is included, during the demolding of the blank and the female mold 1, a flathead screwdriver can be used to remove the blank from the gap between the ejector mold 5 and the female mold 1 (see...). Figure 1 (As shown) By prying upwards the force-applying block 52 of the ejector 5, the lifting plate 51 moves upwards under the action of the force-applying block 52, thereby loosening the solidified blank and finally removing it. See details. Figure 8 As shown, a push-out demolding component 5 is provided at the position of each of the four sides of the forming ring cavity 11. The aforementioned prying operation can be performed on each push-out demolding component 5 in sequence.

[0075] In some embodiments, after the material block is formed by pasting, and before the male mold 2 and female mold 1 are closed, the following steps are included: removing the formed material block from the molding ring cavity 11, and using unidirectional carbon fiber filaments to pass through two adjacent through holes 101 to form a cross hole in the thickness direction of the material block and tighten it. The tightened unidirectional carbon fiber filaments should have sufficient tension (controlled at 8N in a specific embodiment). The specific number of tightening turns depends on actual needs, generally 1 to 3 turns. Then, the tightened material block is placed back into the molding ring cavity 11. In some embodiments, after tightening the material block with unidirectional carbon fiber filaments, a layer of fabric (e.g., 3k twill prepreg) is laid on the top and bottom surfaces of the material block to further cover the tightened filaments and improve the appearance. It is understandable that, taking the orientation of the prepreg in its laid-out state as a reference, the plane on which each prepreg is laid out is the xy plane, and the winding and tightening direction of the aforementioned unidirectional carbon fiber bundle is perpendicular to the xy plane, that is, the z-axis winding.

[0076] In this technical solution, after the prepreg is laid, the entire block is taken out and wound with filaments, which effectively increases the Z-direction layup and significantly improves the interlayer shear strength and anti-delamination performance of the area around the aforementioned through hole 101 and the area between holes, thereby improving the structural stability of the assembly holes of the composite frame component under locking force, machining vibration and service load.

[0077] In some implementations, when the intermediate pressure ring 21 has a positioning pin hole 211 and the intermediate pressure ring 21 is made of a ferromagnetic metal material, when the magnetic switch of the worktable of the machining equipment is in the off state (i.e., the worktable is not magnetic), the intermediate pressure ring 21 is inserted into the positioning pin on the worktable through the positioning pin hole 211 to form a quick pre-positioning. Then, the magnetic switch is controlled to switch from the off state to the closed state (i.e., the worktable is magnetic), realizing the quick positioning and connection of the blank and the worktable without the need for manual adjustment of the product position, which significantly improves production efficiency.

[0078] It will be readily understood by those skilled in the art that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A frame-type composite material molding die, characterized in that, The system includes a female mold (1), a male mold (2), and a top cover plate (4). A forming ring cavity (11) is formed on the top surface of the female mold (1). The male mold (2) includes a middle pressure ring (21), an inner pressure ring (22) located inside the middle pressure ring (21), and an outer pressure ring (23) located outside the middle pressure ring (21). The outer ring wall of the inner pressure ring (22) is in contact with the inner ring wall of the middle pressure ring (21), and the inner ring wall of the outer pressure ring (23) is in contact with the outer ring wall of the middle pressure ring (21). The middle pressure ring (21), the inner pressure ring (22), and the outer pressure ring (23) can work together. The cavity opening of the molding ring cavity (11) is sealed to mold the composite material in the molding ring cavity (11) into a frame blank (100). The frame blank (100) has multiple through holes (101). The intermediate pressure ring (21) and the area corresponding to each through hole (101) have a locking through hole (212). Locking screws (3) are inserted into the locking through hole (212) and the through hole (101) corresponding to each position. The intermediate pressure ring (21) can be positioned and connected to the worktable of the machining equipment. The top cover plate (4) is placed on the side of the male mold (2) away from the female mold (1).

2. The frame-type composite material molding die according to claim 1, characterized in that, The intermediate pressure ring (21) is made of ferromagnetic metal material so that the intermediate pressure ring (21) can be magnetically positioned and connected to the worktable; and / or, at least two positioning pin holes (211) are formed on the side end face of the intermediate pressure ring (21) away from the female mold (1), and each positioning pin hole (211) can be inserted into the positioning pin on the worktable.

3. The frame-type composite material molding die according to claim 1, characterized in that, The screw head (31) of the locking screw (3) is located at one end of its screw shank (32) near the female mold (1), and a nut (34) is screwed onto the threaded section of the screw shank (32) away from the female mold (1).

4. The frame-type composite material molding die according to claim 3, characterized in that, The bottom wall of the forming ring cavity (11) has a groove (111) for accommodating each screw head (31) in the area corresponding to the position of each through hole (101), and the groove (111) and the screw head (31) are anti-rotationally engaged; and / or, the end of the set hole (212) away from the female mold (1) is a countersunk platform, the nut (34) is accommodated in the countersunk platform, and the end of the screw rod (32) away from the female mold (1) is located in the countersunk platform; and / or, the screw rod (32) has a first rod segment (321) that mates with the set hole (212) and a second rod segment (322) that mates with the through hole (101), the wall of the set hole (212) is a conical surface that mates with the first rod segment (321), and the small diameter surface of the first rod segment (321) is located at the end away from the female mold (1).

5. The frame-type composite material molding die according to claim 4, characterized in that, A sealing washer (33) is fitted on the screw rod (32). In use, the sealing washer (33) is embedded in the groove of each of the grooves (111) and its top surface is flush with the bottom wall plane of the molded ring cavity (11); and / or, an axial limiting ring platform (320) is formed at the connection between the first rod segment (321) and the second rod segment (322).

6. The frame-type composite material molding die according to claim 4, characterized in that, The inner pressure ring (22) is composed of multiple inner pressure ring sub-bodies (221) spliced ​​together. The top surface of the female mold (1) has multiple first guide posts (12) spaced apart around the outer edge of the forming ring cavity (11). Each inner pressure ring sub-bodies (221) is respectively fitted with at least two adjacent first guide posts (12) for upper and lower limiting. And / or, the outer pressure ring (23) is composed of multiple outer pressure ring sub-bodies (231) spliced ​​together. The top surface of the female mold (1) has multiple second guide posts spaced apart around the inner edge of the forming ring cavity (11). (13) Each of the outer pressure ring sub-bodies (231) is respectively fitted with at least two adjacent second guide posts (13) for upper and lower limiting; or, the intermediate pressure ring (21) has a pressure ring body and an extension plate (213) extending toward the inner pressure ring (22) and / or the outer pressure ring (23), the extension plate (213) stops on the side end face of the inner pressure ring (22) and / or the outer pressure ring (23) away from the female mold (1) and the extension plate (213) and the side end face of the pressure ring body away from the female mold (1) are on the same plane.

7. The frame-type composite material molding die according to claim 6, characterized in that, The top cover plate (4) has a limiting annular groove (41) on one end face facing the male mold (2) that can accommodate the male mold (2).

8. The frame-type composite material molding die according to claim 1, characterized in that, The female mold (1) is also formed with a plurality of limiting grooves that are spaced around the periphery of the molding ring cavity (11) and penetrate the outer wall of the female mold (1). Each limiting groove is provided with a push-out demolding component (5). Each push-out demolding component (5) has a lifting plate (51) that is below the bottom surface of the frame blank (100) and flush with the bottom wall of the molding ring cavity (11) and a force-applying block (52) that extends to the outer wall of the female mold (1). Each push-out demolding component (5) can apply force to the bottom surface of the frame blank (100) through the force-applying block (52) to demold the frame blank (100) from the molding ring cavity (11).

9. A method for molding a frame-type composite material using a frame-type composite material molding die according to any one of claims 4 to 7, comprising the following steps: The screw heads (31) of each screw rod (32) are positioned in each groove (111) from top to bottom, and the prepreg with pre-made through holes (101) is laid layer by layer in the forming ring cavity (11). Each prepreg is fitted onto each screw rod (32) through its through hole (101), and each prepreg is laid layer by layer to reach a preset thickness to form a block. The middle pressure ring (21), inner pressure ring (22) and outer pressure ring (23) are placed on the female mold (1) to realize the mold closing of the male mold (2) and the female mold (1), and the top cover plate (4) is placed on the top surface of the male mold (2). The mold after mold closing is placed in a hot press device to complete the molding and curing process to form a frame-shaped blank (100). Remove the top cover plate (4), screw a nut (34) onto the threaded section of the locking screw (3) to ensure that the frame blank (100) and the intermediate pressure ring (21) are reliably connected as one unit. Then demold the frame blank (100), each locking screw (3) and the male mold (2) as a whole from the molding ring cavity (11), and after demolding, detach the inner pressure ring (22) and the outer pressure ring (23) from the frame blank (100). The frame-shaped blank (100) is positioned and connected to the worktable of the machining equipment by the intermediate pressure ring (21) on the side end face away from the frame-shaped blank (100); Select one of the locking screws (3) as the reference screw, obtain the position deviation between the original machining coordinate system of the worktable and the reference coordinate system corresponding to the center of the screw head (31) of the reference screw, and when the position deviation is higher than the preset threshold, establish the actual machining coordinate system with the screw head (31) of the reference screw as the reference, and perform machining on the frame blank (100) based on the actual machining coordinate system to form the frame composite material finished product.

10. The method for molding frame-type composite materials according to claim 9, characterized in that, After the material block is formed by pasting, before the male mold (2) and female mold (1) are closed, the process further includes: removing the formed material block from the molding ring cavity (11), and using unidirectional carbon fiber bundles to pass through two adjacent through holes (101) to form a cross hole in the layup thickness direction of the material block for clamping, and then placing the clamped material block back into the molding ring cavity (11); or, When the intermediate pressure ring (21) has a positioning pin hole (211) and the intermediate pressure ring (21) is made of ferromagnetic metal, and the magnetic switch on the worktable of the machining equipment is in the off state, the intermediate pressure ring (21) is inserted into the positioning pin on the worktable through the positioning pin hole (211) to form an insertion fit, and then the magnetic switch is controlled to switch from the off state to the closed state; or, When the position deviation is not higher than the preset threshold, the frame blank (100) is machined to form a frame composite material finished product based on the original machining coordinate system of the worktable.

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